const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    let s = await readline()
    let t = await readline()
    let sLen = s.length
    let tLen = t.length
    let shortStr = sLen < tLen ? s : t
    let longStr = sLen < tLen ? t : s
    let maxStr = ''
    for (let i=0; i<longStr.length; i++) {
        for (let j=i+1; j<longStr.length; j++) {
            let str = shortStr.substring(i, j)
            if (longStr.includes(str) && str.length > maxStr.length) {
                maxStr = str
            }
        }
    }
    console.log(maxStr)
}()